Art of hardening castings.



J. W. G EBHARD.

ART OF HARDENING CASTINGS.

APPLICATION FILED FEB. 12. 1915.

1,239,586. Patented Sept. 11, 1917,

2 SHEETSSHEET 1.

WITNESSES I V i vsm'on J. W. GEBHARD.

ART OF HARDENING CASTINGS.

Patented Sept. 11 1917.

- SHEETS-SHEET 2.

UNITED. STATES PATENT OFFICE.

OHN w. GEBI-IARD,

F VANDERGRIFT, PENNSYLVANIA, ASSIGNOE TO UNITED ENGI- NEERING & FOUNDRYCOMPANY, OF PITTSBURGH. PENNSYLVANIA, A CORPORA- TION OE PENNSYLVANIA.

ART OF HARDENING CASTINGS.

To all whom. it may concern:

Be it known'that I, J OHN N. GEBHARD, a citizen of the. United States,residing at Van'dcrgrif-t, in the county of \Vestmorelaud (and State ofPennsylvania, have invented a new and usefutlmprovement inthe Art ofHardening Castings, of which the following is a full, clear, and exactdescription,

reference being had to the accompanying drawings, forming part of thisspecification, in which-.

Figure 1 is a longitudinal vertical section showing a mold arranged forcarrying out my process.

Fig. 2 is a horizontal section on the irregular line IIII of Fig; 1.

Fig. is a view similar to Fig. 1 showing the casting in place aftercompletion of the operation.

F i g. 4 is a sectional side elevation.

Fig. 5 is a cross section on the line V-V of Fig. 6.

Fig. 6 is a horizontal section, showing another casting in place, .madein accordance with my inventionyand F ig. 7 is a perspective View,partly broken away, showing a vault plate casting made in accordancewith my invention.

My invention relates to the method of making castings, particularlysteel castings having a hardened face orportion formed by a layeriofhardenedmaterial within the mold. The hardened material is oi? anexothermic character, the reaction started therein by the heat of themolten metal, giving of? heat and causing a high temperature;

Heretofore in such processes two diiiiculties have been encountered.First, the reaction liberates gases and the hardening layer must be thinin order to give the proper character of hardened. portion. Hence, thehardened portion is of relatively shallow depth. Seconrhinasmuch 'as thehardening material as it melts occupies less space or volume than itdoes before melting, 1t

shrinks and does not entirely cover the face to be hardened.

My invention overcomes these difficulties and it consists broadly infeeding an additi'onal supply of the hardening material Specification ofLetters Patent. 1

to the face or portion of the casting to be hardened after the meltingof the hardeningmaterial begins.

In carrying out my invention, I provide an additional supply of thehardening ma terial in such relation to the face or portion to behardened that, as the fusing of the hardening material progressivelyproceeds, this supply will be melted and supplied'to the casting. Ia'lsoarrange this additional amount in such a relation that as the hardeningmaterial melts and gives out heat, thus combining with the desiredportion of the casting, space will be provided to allow the slag andgases to arise, thus giving a better character to the hardening portion,relieving it from sponginess, pipes, slag, etc.

I will now describe my. process, referring .to Figs. 1 to 3 of thedrawings, In these figures, 2 represents a sand-mold for easting asteel'stamp-head, 3 the mold shapingcavity, 4 a sink-head cavity risingthere'- from, and 5 a pouring-gate. This gate comaround the core-likeportion 10 and the neck portion 11 of the hardening compound, and thenrises over the portion 9 Within the mold-torming cavity.

Then the mold is filled, and when the steel begins to thicken, thereaction will begin in the hardening compound. Thisreaction sets free alarge amount of heat and will extend progressively through the com-Patented Sept. 11, 1917. Application filed February 12, 1915. Serial No.7,694.

pound which melts and combines with the lower part of the steel casting,remelting this portion oi the castingl As this action pro ceeds throughthe compound it will extend through the neck into the portion 10, and asthese portions melt they will keep molten the interior of the sink-headand its neck connecting with the lower part of the mold,

thus feeding an additional supply of the hardening compound to thedesired surface and at the same time allowing the products of thereaction, such as gas and slag, to rise through the center part of theadditional sink-head.

When the casting is finally chilled and solid, it will be of the generalform shown in Fig. 3. The slag shown at 12 resulting from the reactionof the hardening com pound will lie within the sink'head below its 'topand the hardened portion of the stamp-head will connect with thehardened portion of the sink-head which remained molten after the steelwas solidified.

When the casting is removed from the corresponding to the depth of thehardening material supplied, the heat of reaction, etc.

The hardening composition employed is of exothermic nature, its reactiongiving out a large amount of heat, andI may use difl'en ent kinds ofmixtures. For example, Ihave used a combination of finely groundmanganese, chrome, SiO aluminum-and linseed oil; or a mixture of thesame with nickel.

One mixture which I have employed with success is manganese 4.52 partsby volume,

r .chromium parts by volume, SiO 1 part,

aluminum .1 part, nickel 6 parts and oil 3.5 parts.

' Such compositions have an exothermic reaction which starts after thesteel has been poured in the mold and usually about the head cavities. I

When the molten steel is bottom cast into this mold it will fill themoldand rise within the sink-heads, and as it is beginning to set, thehardening compound-will begin its reaction at the bottom of the layer,this reaction proceeding upwardly, thus melting the compound and theadjacent part of the casting. During the time of reaction the slag andgases will rise, and as the reaction enters the sink-head cavities, theportions of compound therein will feed down into the cavity proper vtosupply the required amount of material for hardening the com- .pleteface of the castingproper. When the entire casting has finally set, thesink-head portions will contain the slag from the reaction in thecavities formerly occupied by the compound. This compound will shrinkand settle more than the steel, thus leaving the cavities shown.

In Fig. 7 I show a cast steel vault plate having the side softerportions ll and the intermediate harder portion 15. In this case thehardening material is prcfeably spread over both sides of a support suchas wire netting, expanded metal or rods. This support is provided withextensions which project up within the sink-head portions of the moldcavity so that the hardening material spread thereon will extend upwithin these cavities. The action will be the same in this case as inthe other cases. the portions 3 of the compound within the sink-head cavmold, the sink-heads are of course cut oil, thus giving a stamp-headwith a face hardened over its entire surface and to a depthities sinkingdown during the reaction and the slag and gases rising to the top withinthe sink-heads.

An additional supply of the hardening reactive compound may be placed inthe sinkhead cavities if desired.

The hardening compound or alloy is proportioned so that it will not betaken up by the steel as it is poured, but will remain in steel at theside or around the compound, the

impurities rising to the top. The alloy portion of the tre ed sectionwill.remain'liquid for some time after the steel has become solid.

The hardening compound is compressed sufiicicntly to hold its shape, butis more or less spongy and contains air. This air will supply sufficientoxygen for the initial reaction; and through the remainder of the fusingaction, air will be drawn in for combustion from and through the formingmold, spch as sand.

The hardening compound is fusible. lhat is, it contains fusible materialso that the compound as a whole will melt and flow. It may, however,contain powdered material which has such a high melting point that itmay not fuse, or at least not completely fuse,

but remain in solution in the fused pompound. By the word fused orfusihle in my' claims, I intend to cover the-"compound whcther it fusesin'whole or in part.

The advantages of my invention will be obvious to those skilled in theart; since any desired surface or portion of the casting may be hardenedthroughout its entire. exteht. as I have overcome the difliculty in.shrinking of the compound layer. Furthermore a better hardened materialis afforded, since the impurities are released :ind allowed to passmore, the hardened alloy portion of the cast- 7 ing is cleaned fromimpurities which are allowed to pass up through this alloy portion whileliquid.

Many variations may be made in the form and arrangement of the mold, thehardening compound and the arrangement and connections for feeding thecompound into the mold cavity, without departing from my invention.

I claim:

l. The methodof making a casting having a hardened portion, consistingin casting the metal into a mold having hardening ma.- terial formed asa part thereof, and feeding an additional supply of the hardeningmaterial into the mold; substantially as described.

2. The method of making a casting having a hardened portion, consistingin casting the metal into a mold cavity containing hardening materialcapable of giving an exotherexothermic reactive mic reaction whilefusing, and feeding additional fused hardening material to the portionof the casting to be hardened as the exothermic reaction proceedssubstantially as described. 7

3. The method of making a casting having a hardened portion, consistingin providing a mold having extensions from the shaping cavity thereof,said mold containing a hardening exothermic reactive material within themold and its extension, and casting the metal thereinto; substantiallyas described.

4. The method of making a casting having a hardened portion consistingin roviding the mold with a layer of exothermic reactive hardeningmaterial extending within and be yond the mold cavity proper, andcausing said extension-portion of the compound to feed into the moldduring the reactive period: substantially as descr'bed.

5. The method of making a casting having a hardened portion, consistingin forming a mold cavity with a sink-head extension. open to theatmosphere, providing the mold with hardening material extending intothe sinkhead ing steel thereinto in contact w th the hardening materialin the mold cavity; substantially as described.

6. The method of making a steel castinghaving a hardened portion,consisting in feeding.the steel into a mold and bringing it in contactwith a. hardening material having an exothermic reaction. material inliquid form to the portion of the casting to be hardened substantiallyas described.

portion, and cast- ,p

and feeding said 7. The method of making a steel casting having ahardened portion, consisting in casting steel into a mold, bringing thesteel into contact with a hardening compound,- having a suflicientexothermic reaction to remelt the steel portion to be hardened and thecompound and thereby form a hardened al- 10y, and feeding the compoundto the part to be hardened as the steel sets; substantially asdescribed.

8. A mold having its. molding cavity provided With an extension, saidmold having a layer of exothermic reactive hardening compoundextendingwithin a part of the moldcavity and its extension, saidcompound being adapted to fuse under the action of the molten metalpoured into the mold; substantial ly' as described.

9. A mold having a sink-head cavity connecting with the molding cavity,the molding cavity and sink-head cavity being pro vided with hardeningcompound adapted to be contacted with and fused by the molten metal;substantially as described.

10. A mold having a molding cavity pro-' vided with an extension, and ahardening compound located within the mold and its extension, andadapted to fuse progressively when contacted with by the molten metalfed into the mold and flow to the portion of the ive a sufficientexothermic reaction to re-.

analloy with the steel throughout said portion; substantially asdescribed.

' 12. A'mold having its molding cavity provided avith an extension, anda.v layer of hardening compound. within the mold cavity and extendinginto the extension, the com pound being adapted to start an exothermicreaction about the time when the steel begins to thicken or set, andfeed sufficient of the hardening compound to alloy with the entireportion of the face to be hardened, substantially as described.

13. A mold having its molding cavity rovided with a cavity extension,and a shaped layer of fusible hardening compound contained within themold cavityand extending within the extension, the hardening compoundbeing arranged to fuse progressively after it is contacted withby'the'molten metal poured into thd' mold and to feed as a fusedcompound to the'surface to be hardened. said compound givingan'exothermic reaction during its progressive fusing, substantially asdescribed.

14. The method of making a casting having a hardened portion, consistinginfeedv Tn testimony whereof, T have hereunto set mg the casting metallnto a mold having my hand.

v I z 7 v a 1113a of haldemng maten 1l pleyloqsb Jon} W. (I L Li {Am}.upphed thewto and progressnely ieedlng fused hardemng materlal to theportlon de- \vltnessosz sued to be hardened to alloy thercw1th,, sub- W.C. LYON, stantlally as described. H. M. Comm);

